class_docstr: Naive preprocessor.
  
  Example:
      >>> import matchzoo as mz
      >>> train_data = mz.datasets.toy.load_data()
      >>> test_data = mz.datasets.toy.load_data(stage='test')
      >>> preprocessor = mz.preprocessors.NaivePreprocessor()
      >>> train_data_processed = preprocessor.fit_transform(train_data,
      ...                                                   verbose=0)
      >>> type(train_data_processed)
      <class 'matchzoo.data_pack.data_pack.DataPack'>
      >>> test_data_transformed = preprocessor.transform(test_data,
      ...                                                verbose=0)
      >>> type(test_data_transformed)
      <class 'matchzoo.data_pack.data_pack.DataPack'>
docstr: Fit pre-processing context for transformation.
  
  :param data_pack: data_pack to be preprocessed.
  :param verbose: Verbosity.
  :return: class:`NaivePreprocessor` instance.
docstr_tok: ["Fit","pre-processing","context","for","transformation",".",":","param","data_pack",":","data_pack","to","be","preprocessed",".",":","param","verbose",":","Verbosity",".",":","return",":","class",":","`","NaivePreprocessor","`","instance","."]
code: def fit(self, data_pack: DataPack, verbose: int = 1):
      """
      Fit pre-processing context for transformation.
  
      :param data_pack: data_pack to be preprocessed.
      :param verbose: Verbosity.
      :return: class:`NaivePreprocessor` instance.
      """
      func = chain_transform(self._default_units())
      data_pack = data_pack.apply_on_text(func, verbose=verbose)
      vocab_unit = build_vocab_unit(data_pack, verbose=verbose)
      self._context["vocab_unit"] = vocab_unit
      return self
  
file_path: MatchZoo/matchzoo/preprocessors/naive_preprocessor.py
imports: from tqdm import tqdm
  from matchzoo.engine.base_preprocessor import BasePreprocessor
  from matchzoo import DataPack
  from .chain_transform import chain_transform
  from .build_vocab_unit import build_vocab_unit
  from .None import units
label_desc: Use image node_id 1 for calling the NaivePreprocessor obj's underlying member method code with example usage: obj.fit(data_pack, verbose) and returns: self